feat(nav): 底部导航改为首页推荐追剧我的

lib/core/theme/app_colors.dart

@@ -69,6 +69,11 @@ abstract final class AppColors {
   /// 底部导航底色。
   static const bar = ink;
 
+  /// 底部导航专用：纯黑背景、选中白、未选中灰与轻分割线。
+  static const navBackground = Color(0xFF000000);
+  static const navSelected = Color(0xFFFFFFFF);
+  static const navDivider = Color(0xFF1C1C1E);
+
   /// 卡片阴影（深色几乎不用阴影）。
   static const cardShadow = Color(0x00000000);
 
@@ -121,7 +126,7 @@ abstract final class AppColors {
   static const badgeBeige = raised;
 
   /// 导航未选中。
-  static const navUnselected = muted;
+  static const navUnselected = Color(0xFF8A8A8E);
 
   /// 播放器次要文字。
   static const playerMuted = Color(0xA3FFFFFF);

lib/core/theme/app_dimens.dart

@@ -36,7 +36,7 @@ abstract final class AppDimens {
   static const double previewCardTitle = 13;
   static const double previewSectionTitle = 14;
   static const double chipFont = 10;
-  static const double navLabel = 12;
+  static const double navLabel = 11;
 
   static const double buttonHeight = 48;
   static const double primaryButtonHeight = 52;

lib/core/theme/app_theme.dart

@@ -193,8 +193,8 @@ abstract final class AppTheme {
         ),
       ),
       bottomNavigationBarTheme: const BottomNavigationBarThemeData(
-        backgroundColor: AppColors.bar,
-        selectedItemColor: AppColors.blue,
+        backgroundColor: AppColors.navBackground,
+        selectedItemColor: AppColors.navSelected,
         unselectedItemColor: AppColors.navUnselected,
         elevation: 0,
         type: BottomNavigationBarType.fixed,

lib/core/widgets/app_bottom_nav.dart

@@ -1,7 +1,5 @@
 // Author: fruit.com.cn
 
-import 'dart:ui';
-
 import 'package:flutter/material.dart';
 
 import '../theme/app_colors.dart';
@@ -26,12 +24,12 @@ class AppBottomNavItem {
   final bool selected;
 }
 
-/// 四槽底部导航：所有页面统一深色底与浅色图标。
+/// 四槽底部导航：纯黑背景，白色选中态，灰色未选中态。
 class AppBottomNav extends StatelessWidget {
   const AppBottomNav({
     super.key,
     required this.items,
-    this.backgroundColor = AppColors.bar,
+    this.backgroundColor = AppColors.navBackground,
     this.barKey,
     this.dark = false,
   });
@@ -47,8 +45,10 @@ class AppBottomNav extends StatelessWidget {
       key: barKey,
       height: AppDimens.navHeight,
       decoration: BoxDecoration(
-        color: dark ? AppColors.bar : backgroundColor.withValues(alpha: 0.96),
-        border: const Border(top: BorderSide(color: AppColors.border)),
+        color: dark ? AppColors.navBackground : backgroundColor,
+        border: const Border(
+          top: BorderSide(color: AppColors.navDivider, width: 0.5),
+        ),
       ),
       child: Row(
         children: [
@@ -60,17 +60,9 @@ class AppBottomNav extends StatelessWidget {
         ],
       ),
     );
-    if (dark) {
-      return ColoredBox(
-        color: AppColors.bar,
-        child: SafeArea(top: false, child: bar),
-      );
-    }
-    return ClipRect(
-      child: BackdropFilter(
-        filter: ImageFilter.blur(sigmaX: 20, sigmaY: 20),
-        child: SafeArea(top: false, child: bar),
-      ),
+    return ColoredBox(
+      color: AppColors.navBackground,
+      child: SafeArea(top: false, child: bar),
     );
   }
 }
@@ -102,7 +94,9 @@ class _NavDestination extends StatelessWidget {
                 child: Icon(
                   item.selected ? item.selectedIcon : item.icon,
                   size: AppDimens.navIcon,
-                  color: item.selected ? AppColors.blue : unselectedColor,
+                  color: item.selected
+                      ? AppColors.navSelected
+                      : unselectedColor,
                 ),
               ),
               const SizedBox(height: 3),
@@ -112,8 +106,10 @@ class _NavDestination extends StatelessWidget {
                 overflow: TextOverflow.ellipsis,
                 style: TextStyle(
                   fontSize: AppDimens.navLabel,
-                  fontWeight: item.selected ? FontWeight.w700 : FontWeight.w500,
-                  color: item.selected ? AppColors.blue : unselectedColor,
+                  fontWeight: item.selected ? FontWeight.w600 : FontWeight.w400,
+                  color: item.selected
+                      ? AppColors.navSelected
+                      : unselectedColor,
                   letterSpacing: 0,
                 ),
               ),

lib/core/widgets/app_root_tab.dart

@@ -0,0 +1,38 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+
+import '../../l10n/app_localizations.dart';
+
+/// 客户端根导航的固定顺序。
+enum AppRootTab { home, recommend, following, mine }
+
+extension AppRootTabUi on AppRootTab {
+  Key get tabKey => switch (this) {
+    AppRootTab.home => const Key('tab-home'),
+    AppRootTab.recommend => const Key('tab-recommend'),
+    AppRootTab.following => const Key('tab-follow'),
+    AppRootTab.mine => const Key('tab-mine'),
+  };
+
+  IconData get icon => switch (this) {
+    AppRootTab.home => Icons.home_outlined,
+    AppRootTab.recommend => Icons.smart_display_outlined,
+    AppRootTab.following => Icons.bookmark_border_rounded,
+    AppRootTab.mine => Icons.person_outline_rounded,
+  };
+
+  IconData get selectedIcon => switch (this) {
+    AppRootTab.home => Icons.home_rounded,
+    AppRootTab.recommend => Icons.smart_display_rounded,
+    AppRootTab.following => Icons.bookmark_rounded,
+    AppRootTab.mine => Icons.person_rounded,
+  };
+
+  String label(AppLocalizations l10n) => switch (this) {
+    AppRootTab.home => l10n.homeTab,
+    AppRootTab.recommend => l10n.recommendedTab,
+    AppRootTab.following => l10n.followingTab,
+    AppRootTab.mine => l10n.myTab,
+  };
+}

lib/core/widgets/subpage_header.dart

@@ -120,6 +120,7 @@ class AppSubpageHeader extends StatelessWidget {
     this.actions,
     this.onBack,
     this.dark = false,
+    this.showBack = true,
   });
 
   final String title;
@@ -128,6 +129,7 @@ class AppSubpageHeader extends StatelessWidget {
   final Widget? actions;
   final VoidCallback? onBack;
   final bool dark;
+  final bool showBack;
 
   @override
   Widget build(BuildContext context) {
@@ -140,8 +142,14 @@ class AppSubpageHeader extends StatelessWidget {
         padding: const EdgeInsets.symmetric(horizontal: _horizontal),
         child: Row(
           children: [
-            AppSubpageBackButton(backKey: backKey, dark: dark, onBack: onBack),
-            const SizedBox(width: _backGap),
+            if (showBack) ...[
+              AppSubpageBackButton(
+                backKey: backKey,
+                dark: dark,
+                onBack: onBack,
+              ),
+              const SizedBox(width: _backGap),
+            ],
             Expanded(
               child: Column(
                 mainAxisAlignment: MainAxisAlignment.center,